A traffic generator is used in data communications networks to transmit pseudo-traffic to a “device under test,” typically a router or switch. If a traffic generator and the device under test are connected so as to form one or more transmission loops, the traffic generator may receive the pseudo-traffic back from the device under test for purposes of monitoring the device's ability to properly classify, buffer, and forward data traffic under conditions that model real-word demands. In the prior art, however, the traffic generators are dedicated devices with a high per-port cost due, in part, to the need for increasingly higher speed processors and memory, for example, since the traffic generator must be capable of achieving the same transmission rates as the routers and switches under test. There is therefore a need to reduce the per-port cost of the traffic generator while maintaining the transmission rates of modern routers and switches.